With a federal government shutdown, padlocks are expected to begin going up Tuesday at the gates of hundreds of national parks across the United States from Alcatraz Island in San Francisco Bay to the Washington Monument. Thousands of visitors will be sent home, and local businesses will suffer.

And if history is any guide, closing America's most scenic and beloved places won't go over well with the public.

During the last government shutdown, for 28 days in 1995, national park closures sparked waves of angry calls to Congress and the White House.

"Once the shutdowns began, the reaction from people who wanted access to the parks was absolutely incredible," Bruce Babbitt, who was U.S. Interior Secretary at the time, said in an interview Monday.

"The first call I got was from the governor of Wyoming, who was having a fit. He was saying 'You have to open Yellowstone. This is an outrage. Do something!'"

The Republican governor of Arizona, Fife Symington, sent National Guard troops to the Grand Canyon in an attempt to keep the park open, rather than risk losing tourism. Eventually, Arizona officials paid the National Park Service through state funds and donations to keep famous sites along the South Rim open.

Public opinion eventually turned against then-House Speaker Newt Gingrich and Republicans in Congress who had pressed for the shutdown as part of a budget stalemate with President Bill Clinton. The shift helped Clinton rebound from low polling numbers and win re-election in 1996.

"The park closures in 1995 made a tangible difference," said Joan Anzelmo, who worked that year as a spokeswoman for Grand Teton National Park. "The visual of park rangers closing down national parks, closing down the Statue of Liberty and the Washington Monument -- keeping Americans out of these iconic American sites -- those visuals were really a strong factor in people understanding what a government shutdown meant. People got mad."

There are 401 national park units in the United States, from Civil War battlefields to redwood forests to vast remote mountain ranges. Last year, 287 million people visited them.

Immediately following a shutdown, all day use visitors will be asked to leave every park, said Stephanie Burkhart, a spokeswoman with the National Park Service. People staying at campgrounds and park hotels will be given 48 hours to leave, she added.

Of roughly 23,000 national parks employees, 20,000 will be furloughed, and only essential law enforcement, maintenance and fire personnel will remain, she said. Major roads that run through parks, like the Tioga Road, a state highway running through Yosemite's high country, will remain open. Back country hikers will be allowed stay until their permits expire.

At the Golden Gate National Recreation Area, which receives 17 million visitors a year, restrooms, visitor centers and parking lots will be closed, said spokesman Howard Levitt. But it will be virtually impossible to keep people off huge beach areas, like Ocean Beach or Crissy Field. Tours to Alcatraz will be canceled starting Tuesday, and tour boat operators will suggest visitors take general trips around San Francisco Bay instead.

The whole idea has small businesses who depend on park tourism, particularly in rural areas, worried.

At the Iron Door Saloon in Groveland, near Yosemite, owner Corinna Loh laid off 35 of her 45 employees last month when the massive Rim Fire closed large sections of the park.

"I'm still trying to recoup from the fire," she said. "I'm cooking, and my husband is bartending. If the park closed again, it would be devastating to businesses around here."

Parks officials say the 1995 closure was wrenching for rangers as well.

"It's especially hard to turn away families who have planned vacations, and people have nonrefundable plane tickets," said B.J. Griffin, who was Yosemite superintendent in 1995. "For some people, this is their once-in-a-lifetime visit. Back in 1995, the anger and the anxiety was properly placed. Visitors knew it was Congress and not our rangers."